This patch tries to solve the problem that data is lost because thereare too many outstanding transmit urb's while trying to executeprintk's to a console. The same is true if you try something like"echo t > /proc/sysrq-trigger".This patch takes the route of forcibly polling the hcd device to drainthe urb queue in order to initiate the bulk write call backs. Thisonly happens if the device is a usb serial console device that setsthe max_in_flight_urbs to a non zero value in the serial devicestructure.

A few millisecond penalty will get incurred to allow the hcd controllerto complete a write urb, else the console data is thrown away.

The max_in_flight_urbs was reduced in the usb_debug driver because itis highly desired to push things out to the console in a timelyfashion and there is no need to have a queue that large for theinterrupt driven mode of operation when used through the ttyinterface.